Paul A. Borsa
Paul A. Borsa, Eric L. Sauers and Derald E. Herling
Arthrometric assessment for glenohumeral (GH) laxity is currently unprecedented in orthopedic practice. Clinical evaluation of GH laxity is based on manual tests that lack objectivity and reliability. We have developed an arthrometer that quantifies AP laxity relative to applied load. Forty healthy shoulders were assessed for AP laxity at 67-, 89-, 111-, and 134-N load levels. A factorial ANOVA revealed significant mean (± SD) differences between directions (p < .0001) and between loads (p < .001). Our results demonstrate the quantified relationship between applied directional loads and GH translation in vivo. We determined bilateral symmetry within subjects and demonstrated excellent reproducibility of the device. Frequency distributions for AP laxity revealed a bell-shaped curve, indicating a normal distribution. Anterior laxity was significantly greater then posterior laxity, and it demonstrated better compliance between the selected load levels.
Paul A. Borsa, Scott M. Lephart and James J. Irrgang
We compared the outcome measures of three knee scoring systems currently used to measure disability in anterior cruciate ligament (ACL)–deficient athletes. Twenty-nine ACL-deficient athletes completed three scoring systems (the Lysholm Knee Scoring System, a modified version of the Cincinnati Knee Scoring System, and the Knee Outcome Survey). Results demonstrate statistically significant mean differences and linear relationships between the outcome measures for the three scoring systems. The Knee Outcome Survey appears to provide valid measures of disability and indicates that our subjects functioned well with activities of daily living but became symptomatic and functionally limited with sports. The outcome measures also indicate that the Lysholm system is more specific to activities of daily living, while the modified Cincinnati is more specific to sports. We recommend that standard scoring systems be developed to provide measures of functional disability in athletes who experience knee injuries.
Paul A. Borsa, Eric L. Sauers and Scott M. Lephart
Functional training for the purpose of restoring dynamic joint stability has received considerable interest in recent years. Contemporary functional training programs are being designed to complement, rather than replace, traditional rehabilitation protocols. The purpose of this clinical commentary is to present a management strategy for restoring dynamic stability in the posterior cruciate ligament (PCL)-injured knee. The strategy presented integrates five key concepts: (a) planned variation of exercise, (b) outcomes-based assessment, (c) kinetic chain exercise, (d) proprioception and neuromuscular control, and (e) specificity of activity. Pertinent research findings and a clinical rationale are provided for using functional training in the restoration of dynamic stability in the PCL-injured knee.
Scott M. Lephart, Mininder S. Kocher, Freddie H. Fu, Paul A. Borsa and Christopher D. Harner
Injury to the anterior cruciate ligament (ACL) is thought to disrupt joint afferent sensation and result in proprioceptive deficits. This investigation examined proprioception following ACL reconstruction. Using a proprioceptive testing device designed for this study, kinesthetic awareness was assessed by measuring the threshold to detect passive motion in 12 active patients, who were 11 to 26 months post-ACL reconstruction, using arthroscopic patellar tendon autograft (n=6) or allograft (n=6) techniques. Results revealed significantly decreased kinesthetic awareness in the ACL reconstructed knee versus the uninvolved knee at the near-terminal range of motion and enhanced kinesthetic awareness in the ACL reconstructed knee with the use of a neoprene orthotic. Kinesthesia was enhanced in the near-terminal range of motion for both the ACL reconstructed knee and the contralateral uninvolved knee. No significant between-group differences were observed with autograft and allograft techniques.
Paul A. Borsa, Scott M. Lephart, Mininder S. Kocher and Susan P. Lephart
Following injury to the articular ligaments, disruption of mechanoreceptors results in partial deafferentation of the joint. This has been shown to inhibit normal neuromuscular joint stabilization, and it contributes to repetitive injuries and the progressive decline of the joint. Assessment of proprioception is valuable in identification of proprioceptive deficits and subsequent planning of the rehabilitation program. A shoulder rehabilitation program must address both the mechanical and sensory functions of articular structures by incorporating a proprioceptive training element within the normal protocol. The objective of proprioception rehabilitation is to enhance cognitive appreciation of the respective joint relative to position and movement, and to enhance muscular stabilization of the joint in the absence of structural restraints. If these objectives are properly addressed, the restoration of the proprioceptive mechanism will prevent further disability of the shoulder joint.
Dana M. Otzel, Chris J. Hass, Erik A. Wikstrom, Mark D. Bishop, Paul A. Borsa and Mark D. Tillman
Context: Following a lateral ankle sprain, ∼40% of individuals develop chronic ankle instability (CAI), characterized by recurrent injury and sensations of giving way. Deafferentation due to mechanoreceptor damage postinjury is suggested to contribute to arthrogenic muscle inhibition (AMI). Whole-body vibration (WBV) has the potential to address the neurophysiologic deficits accompanied by CAI and, therefore, possibly prevent reinjury. Objective: To determine if an acute bout of WBV can improve AMI and proprioception in individuals with CAI. Design and Participants: The authors examined if an acute bout of WBV can improve AMI and proprioception in individuals with CAI with a repeated-measures design. A total of 10 young adults with CAI and 10 age-matched healthy controls underwent a control, sham, and WBV condition in randomized order. Setting: Biomechanics laboratory. Intervention: WBV. Main Outcome Measures: Motoneuron pool recruitment was assessed via Hoffmann reflex (H-reflex) in the soleus. Proprioception was evaluated using ankle joint position sense at 15° and 20° of inversion. Both were assessed prior to, immediately following, and 30 minutes after the intervention (pretest, posttest, and 30mPost, respectively). Results: Soleus maximum H-reflex:M-response (H:M) ratios were 25% lower in the CAI group compared with the control group (P = .03). Joint position sense mean constant error did not differ between groups (P = .45). Error at 15° in the CAI (pretest 0.8 [1.6], posttest 2.0 [2.8], 30mPost 2.0 [1.9]) and control group (pretest 0.8 [2.0], posttest 0.6 [2.9], 30mPost 0.5 [2.1]) did not improve post-WBV. Error at 20° did not change post-WBV in the CAI (pretest 1.3 [1.7], posttest 1.0 [2.4], 30mPost 1.5 [2.2]) or control group (pretest −0.3 [3.0], posttest 0.8 [2.1], 30mPost 0.6 [1.8]). Conclusion: AMI is present in the involved limb of individuals with CAI. The acute response following a single bout of WBV did not ameliorate the presence of AMI nor improve proprioception in those with CAI.
Marc R. Safran, Christopher D. Harner, Jorge L. Giraldo, Scott M. Lephart, Paul A. Borsa and Freddie H. Fu
Proprioceptive deficits have been demonstrated following anterior cruciate ligament (ACL) disruption, but little research exists evaluating proprioception in the posterior cruciate ligament (PCL)-deficient and/or -reconstructed knee. We have studied proprioception in PCL-deficient and PCL-reconstructed knees. The following summarizes our protocol and results of proprioceptive testing of kinesthesia and joint position sense in participants with isolated PCL injuries and those who underwent PCL reconstruction. We studied 18 participants with isolated raptures of the PCL and 10 participants who underwent PCL reconstruction. Proprioception was evaluated by two tests: the threshold to detect passive motion (TTDPM) and the ability to passively reproduce passive positioning (RPP). These assess kinesthesia and joint position sense, respectively. We have shown that isolated PCL deficiency in the human knee does result in reduced kinesthesia and enhanced joint position sense. Thus, the proprioceptive mechanoreceptors in the PCL do appear to have some function. We further found that PCL reconstruction significantly improved kinesthesia at 45° of knee flexion, while 110° was not significantly different between the involved and uninvolved knee in both studies.